Sink



FIG. 1 is a perspective view of my new design for a sink;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left end elevation view thereof;

FIG. 5 is a right end elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The ornamental design for a sink, as shown and described.